1. Field of the Invention
The invention relates to agitator structures used in the mixing of foods and particularly to the mixing of foods such as mashed potatoes to yield a homemade "lumpy" consistency.
2. Description of the Prior Art
Foods, cosmetics, pharmaceuticals and many other materials have long been mixed in kettles or in containers of various shapes and sizes through the use of agitator structures. Mixing of such materials through the use of agitator structures has also been commonly accomplished in the art before, during and/or after heat treatment such as cooking in the case of food materials and the like. While agitator structures can provide a desired mixing capability without the scraping of a kettle wall, for example, scraping elements are often provided so that interior surfaces of a kettle or container can be continually scraped during the mixing process. Agitators capable of mixing food materials while the materials are being heated and/or cooked include the agitator described by Groen, Jr. in U.S. Pat. No. 3,752,057, the Groen agitator having a diagonally mounted shaft which extends into the open end of a mixing kettle with scraping elements being mounted to that end of the diagonal shaft which extends into the mixing kettle. The scraping elements scrape interior surfaces of the kettle and are maintained in contact therewith by virtue of an accurate placement of the diagonally-disposed agitator shaft relative to the kettle. Care must be taken in the placement of the Groen shaft relative to a kettle when using the Groen, Jr. agitator. The Groen, Jr. agitator also finds itsmost convenient use when operated with a mixing kettle which is open to the atmosphere. Agitators operable about a horizontal axis within a mixing kettle or the like are described by Giusti, in U.S. Pat. No. 4,199,266, Giusti providing scraping elements which are mounted in fixed positions on the agitator. Since the scraping elements of Giusti are not capable of pivotal movement by virtue of structure mounting the scraping elements to the agitator, the scraping elements of Giusti do not continuously "track" the interior surfaces of a kettle especially when these interior surfaces are "out of round" as is often the case with cooking kettles. Pardo et al, in U.S. Pat. Nos. 4,571,091; 4,790,667 and 4,818,116 as well as Gabriele in U.S. Pat. No. 5,009,510, describe agitator structures having scraping elements which continuously track the interior surfaces of a kettle within which materials are being mixed, the scraping elements being resiliently biased into contact with interior surfaces of the kettle even when such interior surfaces are "out of round". The agitators of Pardo et al have been shown to be particularly useful in the mixing of food materials which are being heated and/or cooked. The continual and substantially complete mixing and scraping action of the Pardo et al agitators facilitate mixing of food materials without damage thereto and also act to prevent "burn-on" of food materials to walls of a kettle during mixing and/or cooking. The Pardo et al agitators exhibit extremely efficient mixing and scraping actions due in part to the ability of the scraping elements to maintain contact with interior walls of a kettle even when the kettles are not manufactured with perfectly spherical interior surfaces. The scraping elements of the Pardo et al agitators are contoured with scraping edges which conform to localized portions of interior surfaces of a kettle, the scraping elements being spring-biased for pivotal movement to assure contact between the scraping edges and the surfaces of the kettle. The particular mounting arrangements of the scraping elements in the Pardo et al agitators and in the Gabriele agitator allow efficient mixing and/or scraping while allowing the scraping elements to be readily removed from the agitators for cleaning of the scraping elements and of the agitators. The agitators of the present invention can take the form of the diagonal shaft agitator of Groen, Jr. as described above or preferably the horizontal shaft agitators of Pardo et al and of Gabriele as well as other diagonal shaft and horizontal shaft agitators as exist in the art, the Pardo et al agitators and the Gabriele agitator being preferred in combination with the structures of the present invention.
The prior art also includes a consideration of the desirability of producing certain food products such as mashed potatoes with a "lumpy" consistency such as occurs in a "homemade" mashed potato product. The advent of instant food materials such as instant mashed potatoes and the like has resulted in mashed potato products, particularly in commercial food situations, which are perceived as being inferior to mashed potatoes or similar products formed directly from real, cooked whole potatoes. Such instant potato products usually have the characteristic of being extraordinarily "smooth", that is, without lumps such as are characteristic of homemade mashed potatoes formed directly from real, cooked whole potatoes. The present invention provides agitator structures useful in the processing of a mashed potato product which readily, easily and efficiently produces a "lumpy" consistency indicative of the use of real potatoes in the preparation of the mashed potato product. The resulting "lumpy" mashed potatoes, especially in a commercial or institutional food situation, causes the mashed potato product to have a greater perception of value due to the realization by the consumer that the mashed potato product is formed of real potatoes and is not an instant potato product.